Incandescent electric lamp and method of manufacture



Jan. 1 9, 1932. H. D. MADDN INCANDESCENT ELECTRIC LAM AND METHOD OF MANUFACTURE Filed Sept. 9, 1927 M mm N 0 Patented Jan. 19, 1932 UNITED STATES PATENT OFFICE HARRY D. MADDEN, OF MONTGLAIR, NEW JERSEY, ASSIGNOR TO WESTINGHOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA INOANDESCENT ELECTRIC LAMP AND METHOD OE MANUFACTURE Application filed September This invention relates to electrical devices such as incaiulescent electric lamps or the like in which the lightsource 18 positioned in a predetermined relation to the wall of the In the manufzu'ture of certain types of electrical devices such, for example, as an electric incandescent lamp adapted for use in connection with lighting apparatus wherein the light source must be positioned on a focal -line.'it is essential that the light source be positively and accurately positioned with respect to a given portion of the lamp so that the same maybe secured in an apparatus with the light center of the lamp properly positioned. That is, it is essential that a given dimension be maintained between the light source and the bottom or other point on the base since in optical apparatus the distance between the seat for the base and the focal line of a reflector or system of lenses rs fixed.

It has been proposed in the disposition of a filament for optical purposes to provide a relatively expensive adjustable lamp supporting structure. On the other hand, lamps have been manufactured with a standard base and provided with auxiliary. means for obtaining a predetermined dimension between the light source and the base so that when the. lamp was positioned in a socket the light source would be properly positioned with respect to a focal line. The various expedients resorted'to in properly locating a filament resulted from the faetthat in the manufactureof an incandescent electric lamp under the usual standard conditions, certain manufac-, turing inaccuracies occurred so that slight variations occurred in the positions of the filaments with respect to their required focal positions. f

It is, of course, possible that during the manufactureof a large quantity of. lamps that some of the lamps may have the filament properly located but in order to insure a uniform product for use in connection with reflectors or the like. it isnecessary that each lamp be so constructed that the filament will bepositively positioned in a predeter-- mined relation withrespect to the lamp bulb or a given point thereon so that the final posi- 9, 1927. Serial N0. 218,393.

tion of the filament may be determined and maintained to meet the requirements of optical apparatus.

It is an ob]ect of the present invention, therefore, to provide a method of manufacturing an electrical device such as an incanvide a lamp bulb incorporating means for co-' operating with mechanism to permit a retention of the bulbs in uniform predetermined positions. 5

Other objects and advantages of the invention will be understood as the description proceeds.

In practicing the present invention, I utilize an incandescent electric lamp bulb which may be of the usual commercial type having a bulbous or enlarged chamber. The chamber may have a neck extending therefrom and terminating in the mouth or opening ofthe chamber through which the internal structure of the *lamp is introduced. This internal structure is termed a mount and generally includes a flare tube, exhaust tube and arbor which parts are of glass and are fused together'in what is termed a press. Leadingin conductors extend from the .press to the upper end of the arbor. The arbor is provided with-a button from which support wires extend and carry a filament which constitutes the light element or light source of the lamp, the leading-in wires being connected to the ends of the filament.

In the manufacture of incandescent electric lamps it is necessary to support the lamp bulb in a given relation to the mount during what is termed a sealing-in operation. This seal-f gether and sealed, the bulb being subsequent- 5 is termed the sealing-in operation.

In carrying out the above operations to manufacture a lamp, it is necessary that the mount be held in a given position and that the bulb be disposed about the mount in-a given position and it is the practice tosupport the mount by means of a holder which engages the exhaust tube of the mount. The bulb is supported by means of contact members or jaws which engage with the inclined outer surface of the bulb. The jaws may be either movable or fixed, the latter type being known as adapters.

Owing to the fact that the exterior surface of the bulb is of tapered or inclined form and inasmuch as manufacturing conditions of lamp bulbs make it impossible to maintain an accurate dimension of the bulb, it is obvious that when attempting to position a bulb in accurate relation to a lamp mount that certain variations in the relative positions of the bulb and mount will occur owing to the variations that exist'in the dimensions of the bulb. Ordinarily, therefore, a bulb might be supported at diiierent points on its vertical axis.

For the purpose of overcoming the above difiiculty in positioning the bulb in a definite relation to a mount, the present invention provides the usual type of bulb with means means so that each bulb may be positioned in a definite relation to a mount. In the smaller types of bulbs it is found that by providing a protuberance or annulus about the bulb as, for example, in the plane of the largest diameter of the bulb, the bulb may be held by jaws or by fixed members in a predetermined position. In the larger types of bulbs the protuberance or annulus may be provided on the neck of the bulb as disclosed in my copending. application Serial No. 218,392, filed September 9, 1927. The annulus may be engaged by movable or fixed jaws of the. holding means. However, if desirable, both the bulb proper and the neck thereof may be provided with an annulus or groove. That is, a bead or collar may be provided about the spherical portion of the bulb and a bead or collar may be provided about the neck of the bulb and two sets of jaws may be employed.

It will be evident that bulbs as above constructed "provide a point on the bulb which may always be in the same relative position, thus giving a definite working basis so that .a filament-may be positioned within the bulb in a given relation to a given point on the bulb and a base for the bulb may be applied so that the same will be in a fixed relation to the saidpoint with a consequent determine;

whereby it may cooperate with the holding neck of the bulb.

with the filament in a predetermined position and although the lamp bulbs may possess variations in their diametrical dimensions the cooperation of the bulb with the I holding means makes it possible" to manufacture lamps in which the filaments are uniformly positioned.

The invention will be more fully understood by reference to the accompanying drawin gs in which:

Fig. 1 is an elevational view of an incandescent electric lamp bulb embodying the present invention supported in a holder and partially broken away;

Fig. 2 is a fragmentary view of the bulb shown in Fig. 1 having a. base attached thereto;

Fig. 3 shows a modification of the invention in which a bulb is supported in a holder by engagement with an annulus about the spherical portion of the bulb; and,

Fig. 4 is a view similar to Fig. 3 which lsgpgvs a base in position for attachment to a Although the invention isapplicable to va rious types of electrical devices employing a sealed container or the like, it is shownand described in connection with anincandescent electric lamp.

A bulb 10 is shown which may comprise an enlarged chamber 11 having a neck 12. The said neck is provided with a bead or protuberance 13 in the form of an annulus which surrounds the neck. The neck 12 terminates in the mouth 14 of the bulb 'into which is sists of the flare tube 16 and an exhaust tube 17 and an arbor 18 of glass. These parts are united at 19 in what is termed a press. The lead-in wires'20 and 21 extend from the press and are secured at their upperends to a filament 22 which filament is secured to support wires 23 which extend from the arbor 18.

For the purpose of sealing a mountto a bulb a head or holder 24 is provided having lateral support members or jaws 25 and 26 and a central holder or mount rod 27 into which an exhaust tube of a mount is inserted. The head 24 may be provided with a cross head 28 secured to a spindle 29 which is rotatable in a bearing 30 which forms part of a carrier or conveyor 30' upon which a pluduring a rotation of the head so as to render the flare tube plastic and fuse the saine to The present type of head is especially constructed to support a bulb having an annulus 13 and for this purpose is provided with jaws 33 and 34. These jaws may be so arranged that the bulb may be inserted into the head and seated upon the jaws, thus determining the position of the bulb upon its vertical or longitudinal axis and holding it 1n a given present' preferred form by reason of its adaptability to glass blowing.

hen a mount and bulb are positionedf'or consolidation in a head, they are sealed at 37 as indicated 'in dotted lines. While the seal. or union is still plastic, the mount rod or holder2'i' is moved to change the relative position of the mount within the bulb so that the final position of the union may be at 38. The downward movement of the mount rod 27 may be accomplished in the usual manner.

by lever 39 pivoted at 40 and having a forkedshaped end 41 engaging a collar 42 at the lower end of the mount rod. This relative movement of the mount within the bulb ment with respect to a-given point on the bulb. For example, a given distance, indicated by letter K between the filament 22 and a point 43 on thebulb may be attained either by the initial accurate positioning of the mount or by the approximate disposition of the mount within the bulb and a final adjustment thereof by reason of the relative movement while the seal is still plastic, this movement being generally known as the pull down operation.

Then the mount has been properly adjusted with respect to the bulb and sealed therein. it will be evident that a lamp base 44 as shown in Fig. 2 may be applied to a bulb and secured by a cement 45. The base may have a shoulder 46 for engaging the collar 43 of the bulb so that it may be possible to maintain a predetermined distance indicated by the reference letter Y between the end 47 of the base and the point 43 on the bulb, thereby making it possible by reason of the fact that the point 43 is a predetermined distance with respect to the filament, to obtain a given distance between the end 47 of the base and the filament 22.

.Lamps may, therefore, be constructed so that when seated in a socket associated with be evident that whereas, heretofore it was necessary to depend upon the personal attention and integrity of an operator to properly msition the relative lamp parts, the present invention alfords means whereby the relative positions of the parts are mechanically determined.

In the smaller types of lamps it may be desirable to provide a point on the spherical surface of'thc bulb for the engagement of jaws and as shown in Figs. 3 and 4 a bulb 50 is illustrated having a filament 51 supported on a mount 52. The bulb is provided with a depression or annular groove 53 which in the present instance, is formed by making the top or hemispherical portion of the bulb slightly'larger in diameter than the lower portion. It is obvious, however, that instead of making a groove a bead or collar might be provided around the bulb.

The above type of bulb may be held in a head 54 and seated upon jaws 55. The operation of sealing in the bulb may be the same as described for the bulb shown in Fig. 1 so that a filament 51 may be positioned with the distance indicated by the reference letter A a given dimension from a point 56.

After the mount is sealed into the bulb as above indicated, a base 57-may be-applied thereto by means of a suitable holder 58 (see Fig. 4) while the upper end of the bulb may be held by a clamp 59. The base may be provided with a quantity of cement 60 so that when the holder 58 is moved upwardly to apply the base to the bulb the cement will secure the bulb and base together. It is generally the practice to then pass the base and bulb through an oven so that the cement may be properly baked or set. This operation, of course, depends upon the character of the cement used, that is, whether it isa cold setting cement or one which must be .heat treated.

The base may be so constructed that its upper perimeter when engaged with the neck of the bulb will bring the end 61 of the base a given-distance from the point 56 on the bulb so that the dimension indicated by the letter B may be predetermined. It will therefore. be evident that inasmuch as the distance between the point 56 and the filament is mechanically attained and the distance between the end of the base and the point 56 is also mechanically attained that the distance indicated by the reference letter C will also be uniform, thus providing a.

A lamp bulb-made in accordance with the present invention readily lends itself to autoor projection lamps had heretofore been accomplished by a combination of automatic and manual operations. Usually a conveyor was provided to receive bulbs with bases applied thereto and to intermittently move the bulbs and bases through a given path in a plurality of steps during which the lead wires or conductors were soldered to the base and the base subjected to a heat treatment to bake the cement.

In order to properly position the base upon a lamp bulb, the above mentioned operations included the manual adjustment of the base while the cement was still plastic. The adjustment was accomplished with the aid of optical means to position the base a predetermined distance from the filament, after which the cement was permitted to harden and the base remained in its adjusted position.

By reason of the present invention as heretofore set forth, a lamp filament may be mechanically positioned in a predetermined position within a bulb and at a given distance from a point thereon as, for example, the annulus or collar 13. According to the present invention, therefore, a bulb with the mount sealed therein may have a base 44 applied thereto bymeans (as for example, the holder 58 shown in Figs. 3 and 4) which will automatically move the base so that the shoulder 46 of the base will engage with the annulus or collar upon the bulb, thus providing a mechanical operation for determining the position of the end of the base with respect to the filament.

It will be evident that by reason of the present construction the entire operations for basing a lamp may be performed automati' cally and positively without the aid or attention of an operator.

It will be, evident from the-foregoing that the invention provides a lamp bulb so formed as to facilitate the production of what is termed aprecision lamp or one which may be used for projection purposes. Furthermore, whereas, it is possible to accurately manufacture a lamp under ordinary conditions with extreme care and the exercise of skill on the part of the operator, the present invention provides a methodwhereby lamps ma ibe produced in great volume with rapidity and with uniform specified dimensions as is required between certain of the component parts of the respective lamps. The removal of skilled labor and the time elements due to the laborious operation of manua'lly adjusting'tligflamp parts, makes it evi- I'dent that the present invention constitutes a decided advancedstepiain the art.

candescent electric lamp which comprises forming an annulus upon a lamp bulb, supporting the bulb by engagement with said annulus, adjusting a lamp mount within the bulb to position said mount ina predetermined relation to said annulus and sealing the mount to said bulb.

2. The method of manufacturing an incandescent electric lamp which comprises forming a collar upon a bulb neck, supporting the bulb by engagement with said collar, adj usting a lamp mount within the bulb to position said mount in a redetermined relation to said collar and sea ing the mount to the bulb.

3. The method of manufacturing an incandescent electric lamp which comprises forming a collar upon a bulb, supporting the bulb by engagement with said collar, positioning a filament carrying mount within the bulb, applying heat to fuse the mount to the bulb and adjusting the mount while the fused portion of the bulb and mount is still plastic to dispose the filament a predetermined distanc'e from said collar. 4. The method of manufacturing an incandescent electric lamp which comprises forming a shoulder upon a bulb neck, supporting the bulb by engagement with said shoulder, disposing a lamp mount within the bulb, applying heat to fuse the bulb to the mount and in changing the relative positions of the bulb and mount while the fused portion is still plastic to position the mount in a predetermined relation to saidshoulder.

5. The method of manufacturing an incandescent electric lamp which comprises forming a lamp bulb Witha protuberance, supporting the bulb by engagement with said protuberance, disposing a lamp mount within the bulb, applying heat to fuse the bulb and mount together and in causing a relative movement between said bulb and mount to bring the mount to a predetermined position with respect to said protuberance.

6. The method of manufacturing an incandescent electric lamp which comprises forming a shoulder upon a lamp bulb, supporting the bulb by engagement with the shoulder, positioning a mount within the bulb and adjusting the mount to position the same in a predetermined relation to said shoulder providing a base with ashoulder a predetermined distance from an end thereof and applying said base to the bulb to bring the shoulder of said base and the shoulder of said bulb into contact.

7. A sealing-in machine having bulb engaging means the combination therewith of a. bulb having means inte ral therewith disposed in a predetermined position for vengagement with said bulb engaging means.

8. A sealing-in machine havingbulb engaging means with the combination therewith of a bulb having means integral therewith disposed in a predetermined position for engagement with said bulb engaging means, means for supporting a stem within said bulb and means for sealing saidstem to said bulb. 9. A sealing-in machine having stem supporting means and bulb engaging means the. combination therewith of a bulb having a projection disposed a predetermined distance from a given point on said bulb for engagement with said bulb engaging means to support said bulb in a given relation to a stem in saidstem supporting means.

10. A sealing-1n machine having steni sup porting means and bulb engaging meansthe combination therewith of a bulb having a projection disposed a predetermined distance from a given point on said bulb for engage-- ment with said bulb engaging meansto sup! port said bulb in a given relation to a stem in said stem supporting means, and means for sealing a stem to said bulb.

11. A sealing-in machine having stem sup-- porting means and bulb engaging means the combination. therewith of a bulb having an annulus disposed in a predetermined position with relation to the determined light center of the bulb for engagement with said bulb engaging means to hold the bulb in definite predetermined relation to a stem in said stem supporting means.

12. A sealing-in machine having stem supporting means and bulb engaging means the combination therewith of a bulb having an annulus disposed in .a predetermined position with relation to the determined light center of the bulb for engagement with said bulb engaging means to hold the bulb in definite predetermined relation to a stem in said stem supporting means, and means .for sealing said stem to said bulb.

In testimony whereof, I have hereunto subscribed my name this 8th day of September, 1927.

HARRY D. MADDEN. 

